A single handle control apparatus can be used on a work vehicle, material conveying system, or in other applications where it is desirable to move a single handle to select and control operations. For example, such a control apparatus is commonly used on a track-type tractor to select and control forward or reverse travel of the vehicle. In a hydrostatically controlled tractor, it is preferable to avoid mechanical linkage and to hydraulically connect the control apparatus directly to a hydrostatic transmission of the tractor.
The present invention is directed to overcoming the problems associated with providing a single handle control apparatus for directly moving separate hydraulic valve spools in respective valves in order to operate the hydrostatic transmission and perform separate work operations associated with a respective valve. Therefore, it is desirable to provide means for selectively and progressively moving each of the valve spools of a respective valve in response to moving a single control handle.